Today’s article by Caleb Ferguson and Patricia Davidson on the dangers of energy drinks highlights one of the key themes of this blog “Sola dosis facit venenum”. Energy drinks owe their stimulating property mostly to caffeine and caffeine-like compounds. Caffeine and its relatives theophylline (tea) and theobromine (chocolate) heighten our alertness. This caffeine boost is part of the pleasurable effect of a good cup of coffee

Coffee has even been used as a medicine, due to its caffeine content. In the 1890’s two strong demitasse cups of coffee were recommended for asthma sufferers. The caffeine in coffee relaxed the muscles in the bronchial tubes of the lungs, making breathing easier. These days we still use caffeine’s relative, theophylline, to treat asthma.

Caffeine may be medicine, but, and you know I’m going to say this, “the dose makes the poison”. Caffeine also makes the heart beat faster and stronger, and high concentrations of caffeine can cause severe heart problems (amongst other things) and death. One of the problems with energy drinks is that, especially in combination with alcohol, you can more easily get an overdose of caffeine than, for example, slugging back double espressos.

So how much caffeine will kill you? Luckily there is a handy website where you can find out how many cans of energy drink, cups of coffee or bars of chocolate you will need to consume before expiring. Death by Caffeine.

While some of the figures are reassuringly high, people vary with their sensitivity to caffeine, and their ability to break it down. Worryingly, research recently reported in the Medical Journal of Australia showed that people drinking no more than the recommended amount of energy drinks showed significant signs of toxicity (like palpitations and even parts of their heart muscle dying).

In fact the average consumption of people presenting to the emergency department was between 3-8 cans (although one heroic individual consumed 80 cans). These figures show that some people are far more at risk than the simple calculator suggests.

Also, while Death by Caffeine suggests that chugging back 30 cups of espresso one after the other won’t kill the average person (you need more like 156 for an 80 kg person), you certainly won’t feel bright and shiny at the end (indeed with the gastrointestinal effects, your end will be anything but shiny).